Ultrasonic cleaning of grinding wheels



March 10, 1964 A. KURIS ETAL 3,

ULTRASONIC CLEANING OF GRINDING WHEELS Filed June 13y 1961 4 Sheets-Sheet 1 INVENTORS. ARTHUR KURIS 6| LEWIS BALAMUTH their ATTORNEYS FRESH COOLANT SUPPLY March 10, 1964 A. KURIS ETAL 3,123,951

ULTRASONIC cmmmc' 0F GRINDING WHEELS Filed June 13, 1961 4 SheetS Sheet 2 INVENTORS ARTHUR KURIS 8:

LEWIS BALAMUTH their ATTORNEYS March 10, 1964 A. KURIS ETAL 3,123,951

- ULTRASONIC CLEANING 0F GRINDING WHEELS Filed June 15, 1961 4 Sheets-Sheet 3 lllll lllllllllllfli 'II 6 &

.4 102d 6 Flat 55 INVENTO ARTHUR KURIS LEWIS BALAMUTH wriwjlwaw their AT T OR/VE Y5 March 10, 1964 A. KURIS ETAL 3,123,951

ULTRASONIC CLEANING 0F GRINDING WHEELS Filed June 13, 1961 4 Sheets-Sheet 4 INVENTORS'. ARTHUR KURIS 8| LEWIS BALAMUTH w M M their ATTORNEYS United States Patent F 3,123,951 ULTRASONIC CLEANENG 0F GRINDING WIEELS Arthur Kuris, Riverdale, and Lewis Balamuth, New York,

N.Y., assignors to Cavitron Ultrasonics, Inc., a corporation of New York Filed June 13, 1961, Ser. No. 116,777 21 Claims. (til. 51-262) limited by the loading or clogging of the working surface of the grinding wheel by the fragments of metal debris removed from the work piece. When this occurs, the grains of the abrasive wheel are no longer able to eflectively cut the Work piece and the wheel must be cleaned. This is normally accomplished by dressing the wheel with a pointed tool to remove the impacted debris material on its surface and thus clear it for further grinding operation. During dressing, of course, no grinding is be ing done by the wheel. The dressing operation, which usually uses a diamond-pointed tool, also results in a removal of some of the abrasive material from the grinding surface of the wheel which substantially decreases its Working life. Repeated dressing is necessary, especially when grinding softer metals such as brass, since partially or fully loaded abrasive wheels not only do not grind efliciently, but are incapable of producing the smooth finish required in many applications.

It is a primary object of the present invention to provide novel apparatus for maintaining the working surface of a grinding wheel free from impacted debris material during normal operation thereof.

Another object of this invention is to provide ultrasonic cleaning apparatus for grinding wheels utilizing cavitational action that is simple in operation and which may be attached to existing grinding machines with a minimum of parts re-arrangement thereof.

Still another object of this invention is to provide a novel debris removing tool or shoe for use with ultrasonic cleaning apparatus for grinding wheels.

A further object of this invention is to provide an ultrasonic cleaning apparatus for a grinding wheel wherein the impacted debris material can be readily loosened from the grinding surface of the wheel and removed from the area of the grinding operation.

An additional object of this invention is to provide a novel supply means for a fluid acting as both a coolant for a grinding Wheel and a cavitational medium for ultrasonic apparatus associated with the wheel.

The grinding wheel cleaning apparatus of this invention includes a transducer which is vibrated by a suitable oscillator at high frequencies and arranged to drive a cleaning tool or shoe. Preferably, one end of the cleaning shoe is rigidly coupled to the vibratory end of the transducer by a connecting body, with the cleaning shoe and connecting body having a combined length substantially corresponding to a half wave length or an integral number of half Wave lengths of sound traveling longitudinally through the material of the connecting body and cleaning shoe at the frequency of vibration of the transducer, and are further preferably designed to function as acoustic impedance transformers to provide both primary and secondary magnification of the amplitude of the longitudinal vibrations produced by the transducer. The

3,123,951 Patented Mar. 10, 1964 other end of the shoe is provided with recess forming flanges along the opposite sides thereof and which are designed to overlap the sides of the grinding wheel with minimal clearance therebetween. The inset cleaning face of the cleaning shoe substantially con-forms to the grinding surface of the grinding wheel to which the shoe is applied. One or more fluid discharge apertures are provided in the shoe cleaning face, in communication with one or more passages formed internally in the cleaning tool or shoe, and through which -a cleaning fluid capable of supporting cavitation is applied to the fluid discharge aperture or apertures in the cleaning face of the shoe. The wheel cleaning apparatus may be adjustably connected to and supported by the grinding wheel housing, and a micrometer adjustment may be provided for manually positioning the cleaning face of the tool withrespect to the adjacent peripheral grinding surface of the grinding wheel.

An important feature of this invention is the provision of a cleaning shoe or tool which is shaped, formed and designed to provide a secondary amplification of the longitudinal vibrations as initially amplified by the connecting body, so that the working face of the tool has a relatively long motion stroke which is several times the amplitude of vibrations initially delivered to the connecting body by the energized transducer. This secondary amplification is effected by making the vibration output end of the tool of smaller cross-sectional area than the cross-sectional area of the vibration input end thereof, irrespective of the width of the wheel periphery to which the tool is applied. This secondary amplification is in part accomplished by reducing the arcuate length of the working face to a length less than the corrresponding dimension of the vibration input end of the tool.

A further feature of this invention is the injection of a uniformly distributed supply of cavitational fluid through the working face of the tool, in sufiicient quantity and under suificient pressure, to fill the spacing gap between the tool working face and the adjacent rotating grinding periphery of the wheel, and then confining the injected liquid within the spacing 'gap with minimal leakage between the side flanges of the tool and the sides of the grinding wheel; to the end that an evenly distributed and uniform liquid layer is confined and pocketed within the spacing gap which can be effectively and uniformly cavitated.

As a further feature, the spacing gap defined between the working face of the tool recess and the adjacentperipheral grinding surface of the grinding wheel is adjusted so that the fluid layer injected into and uniformly distributed in the spacing gap, will result in vigorous debris-removing cavitation from the adjacent peripheral grinding surface of the rotating grinding wheel, without appreciable evidence of erosion of the working face of the tool.

The present applicants have discovered that; by providing a cleaning tool which operates as a secondary amplitude magnifier to thereby further increase the amplitude of longitudinal vibration of its working face, with corresponding reduction in the arcuate length of its working face to effect this result regardless of the width of the grinding wheel surface to be covered thereby; and by injecting the cavitational fluid through the working face of the tool in sufiicient quantity, under sufiicient pressure and in a manner to establish a uniform and evenly distributed fluid layer in the spacing gap; and by further confining the fluid layer within the cleaning gap during wheel rotation so that the fluid layer is fully maintained at all times during working rotation of the wheel until discharged from the spacing gap in the direction of wheel rotation; and by displacing the working face of the tool from the rotating wheel surface to' provide a spacing gap of such depth that effective fluid cavitation occurs at the peripheral grinding surface of the wheel, but with no appreciable evidence of erosion of the tool working face, and further away from the peripheral surface of the rotating wheel than was previously considered feasible; highly important and unexpected results are achieved. These results, achieved by the use and practice of this invention, include (a) maintenance of the grinding surface of the rotating Wheel relatively free of debris while performing grinding work over an extended grinding period before wheel dressing is required, (b) greatly increased grinding wheel life, greater grinding accuracy and finer surface texture and finish of the workpiece, (d) higher grinding work output per man hour with minimum rejects, (e) longer tool life, and (f) in general, a very substantial increase in grinding production eificiency.

The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description thereof, when taken in conjunction with the appended drawings, in which:

FIGURE 1 is an elevation of a conventional grinding machine with the cleaning attachment of the present invention in place thereon;

FIGURE 2 is a side elevation of the grinding machine and cleaning attachment, with certain parts shown in section, and as the same would appear when viewed along line 22 of FIGURE 1;

FIGURE 3 is a section through the vibrator assembly of the cleaning attachment as the same would appear when viewed along line 33 in FIGURE 2;

FIGURES 4A through 5B and FIGURES 6 through 10 illustrate various embodiments and modifications of the cleaning tool or shoe and various cavitational liquid feed arrangements at the cleaning face of the cleaning tool; and

FIGURE 11 illustrates an arrangement for collecting debris material dislodged from the grinding surface of the Wheel by the cleaning tool of the present invention.

FIGURES 1 and 2 illustrate a typical grinding machine 10 of conventional type, having a grinding wheel 12 mounted on a shaft journaled Within a shaft housing 11. The grinder includes a work supporting table 13 having a work piece holding surface 15 of any suitable type known in the art, and the grinding wheel 12 is vertically adjustable to control the depth of cut. The table 13 generally is arranged to horizontally reciprocate in both directions to thereby pass the work piece 14 back and forth under the wheel 12. Means are also provided to adjust the work piece supporting table 13 perpendicularly with respect to the wheel 12.

The grinding wheel 12 is provided with a conventional wheel guard 16, parts of which have been removed in FIGURES 1 and 2 for purposes of the illustration. A bracket 17 mounted on the wheel guard 16 supports a nozzle arrangement 18 through which cooling fluid is supplied to the grinding area between the wheel and the work piece. A suction device 20 is also provided to withdraw particles of debris material removed from the work piece 14. Cooling fluid is supplied to the nozzle 18 by means of a pump 58 which forces the fluid through conduit 52 and thence into conduit 19 to the nozzle. The work piece supporting table 13 is provided with a rim and thus forms a catching tray for the coolant, which is returned via conduit 54 and filter 56 back to the pump 58. A fresh coolant supply is coupled through tube 60 and valve 62 to the pump so that fluid that has been lost during the normal grinding process may be replaced as needed. All of the above-described grinding machine structure is conventional and has been included merely to provide a background for explaining the construction and operation of this invention.

The grinding wheel cleaning attachment or apparatus 31) of the present invention, and shown in FIGURES 1 and 2 in assembled relation to a grinding machine structure, may be supported by a support plate 22 which is fixed to the shaft housing \11 and mounted on positioning blocks 23 and 24 adjustably secured to plate 22. An angle bracket member 35 has a horizontal leg dovetailed with block 24 for slidable movement in relation thereto, and a vertical leg having a longitudinal slot for adjusta'bly receiving a mounting bolt 35' projecting from the wheel cleaning apparatus 30. It will be realized, of course, that this mounting structure may be varied as desired to accommodate the particular design of the grinding machine being used.

The wheel cleaning apparatus 30 embraces a vibrator assembly 32 which includes a vibrator unit presenting a transducer section 8t having one end thereof rigidly fixed to one end of an amplitude increasing connecting body 82 and whose other end is rigidly secured to the vibration input end of a cleaning shoe 34 as shown in FIG. 3. The transducer section 30 and a part of the connecting body 82 is contained within a generally cup-shaped housing 84 whose open end is mounted on a support block 36 which is slidably connected by a dovetail connection to a mounting member 38, and which is in turn fixed to the vertical leg of angle bracket 35. Support block 36 is slidably adjusted with respect to support member 38 by means of a micrometer hand wheel 4%, and whereby precise positioning of the working end of the cleaning tool With respect to the grinding wheel may be effected.

As shown in FIGURE 3, the open end of the vibrator housing 8 2 is fitted within a pocket formed in the mounted block 36, with a resilient sealing ring 87 positioned therebetween. A gas or liquid coolant is introduced into the vibrator housing 84 by tube 64 coupled to the closed end of the housing, to thereby cool the transducer section and that part of the connecting body 82 contained in the housing 84. The warmed coolant is withdrawn through a bore formed in the mounting block 36 and which is connected to a warmed coolant withdrawal tube 66.

The transducer section 8% of the vibrator unit is energized and longitudinally vibrated by a surrounding and high frequency alternating magnetic field established by a coil winding wound on a relatively thin intermediate tubular Wall section 84- of the housing. The housing 34 is composed of a non-conductive resin such as nylon, as indicated in FIGURE 3, which does not impede the penetration of magnetic flux therethrough. The coil winding 85 is supplied with biased alternating current of selected high frequency by a pair of current conductors 68 extending through a longitudinal bore formed in the head portion of the housing 84. A current junction box 72, as shown in FIGURE 2, couples the conductors 68 to an oscillation generator (not shown). The vibrator assembly 32, as shown in FIGURES 1 and 2, may be housed in any convenient case 70 having an access cover (not shown) to effectively seal the vibrator assembly 32 against dirt and damage. Cavitational fluid under pressure is introduced to the cleaning face of the tool 34 by means of a tube 42, fixedly supported from the block 36 by support rod 44.

It has been found that several commercial fluids, commonly used to cool and lubricate the grinding wheel and work piece area being ground or polished, possess properties necessary to support cavitation, and the same fluid supplied by fluid line 52 may be used for both purposes. Accordingly, the tube 42 which supplies fluid for cavitational purpose to the cleaning tool or shoe 34, may be connected by a flexible tube -45, a secondary fluid filter 48, a flow control valve 50, and a fluid receiving bore in support plate 22, and which bore is directly connected to the main fluid supply line 52, as shown in FIGURES 1 and 2. The fluid ejection nozzle 18, positioned adjacent the work area being ground or polished, may be connected by branch tubing 19 to the main fluid supply line 52, so that the same fluid also serves as the grinding wheel and work piece lubricant and coolant. It will be appreciated that the pump 58 drives the fluid through supply tube 52 in sufiicient volume and under sufficient pressure to provide an adequate cleaning fluid supply for both the ejection nozzle 18 and tube 42, and that the volume and pressure of cleaning fluid supplied by tube 42 to the cleanin-g tool or shoe may be further adjustably controlled by the valve 50.

The transducer section '86? may be any one of a number of electromechanical types, such as electrodynamic, piezoelectric, or magnetostrictive. The operating frequency may be in the high sonic or ultrasonic ranges, but preferably is in the order of 20,060 to 40,000 cycles per second. At these frequencies, a transducer section 80 of the magnetostrictive type is most desirable. The transducer section 80 may be formed of a stack of plates of a metal such as penna-nickel, permandur, or other metals which have high tensile strength and are highly magnetostrictive in character, so that the transducer section will longitudinally vibrate to a maximum degree when subjected to the influence of an alternating magnetic field, such as is established by the biased alternating current supplied to the Winding 85 in surrounding relation to the transducer section.

The connecting body 82 is rigidly secured at one end thereof to the transducer section 80 by silver solder or other permanent fastening. The connecting body 82 is formed of a material of high tensile strength and vibration transmitting capability, and is so shaped and formed as to increase the amplitude of longitudinal vibrations transmitted therethrough. The cleaning shoe or tool 34, as shown in FIGURE 3, may be permanently, or detachably but rigidly connected, to the vibration output end of the connecting body 82. The cleaning tool 34 may be formed of the same metal as the body 82, or of a different metal of high tensile strength and capable of transmitting longitudinal vibrations therethrough. The detachable connection, when used, may comprise a stud having an enlarged inteirnediate body section 92. of polygonal form to which a wrench may be applied, and from which opposite stud sections 9495 extend which are oppositely threaded for mating engagement with threaded holes formed in the vibration output end of the connecting body 82 and the vibration input end of the cleaning shoe 34, as shown in FiGURE3. By providing a detachable connection such as the threaded stud 92, the cleaning tool 34 may be made of a different metal, such as an aluminum alloy, than the connecting body 82, and may be removed and replaced by another cleaning tool having a working face 1% of different area and width.

The transducer section 80, connecting body 82 and cleaning shoe 34 may be unitarily assembled to provide the vibrator unit, and the vibrator unit is mounted or suspended in the mounting block 36 by providing the connecting body 82 with a nodal flange 83 located at the approximate nodal area of longitudinal vibration thereof.

The nodal flange 83 is provided with a peripheral groove which receives a resilient mounting and sealing ring 86 positioned to abut against a longitudinal shoulder formed in the bore of the mounting block 3-6, and held in sealing position by means of a retainer ring 88 and a threaded plug ring 90 which is threaded into the bore of the mounting block 36 as shown in FIGURE 3. Thus, the entire vibrator unit comprising the transducer stack 80, connecting body 52 and cleaning tool 34 may be withdrawn from the mounting block 36 and housing 84, and replaced with another vibrator unit as desired. When the vibrator unit is in mounted position, with the sealing ring 36 locked in mounted position by the retainer and plug rings 88 and 9h, undesired leakage of the transducer coolant from the coolant chamber defined within the housing 84 and mounting block 36 is prevented.

The transducer section 8t connecting body 32 and cleaning shoe or tool 34 each having a longitudinal length which substantially corresponds to an integral number (preferably one) of half wave lengths of sound traveling longitudinally through the material thereof at the frequency of the alternating magnetic field which energizes the transducer stack 8%, as supplied by the winding 85 and the frequency adjustable oscillation generator connected thereto. Primary amplification of the longitudinal vibrations injected by the energized transducer stack into the input end of the connecting body 82 is effected by making the vibration input section 82 on one side of its nodal flange 83 of substantially greater mass than its output section 82" on the opposite side of its nodal flange 83. Secondary amplification of the longitudinal vibrations injected into the input section 34' of the cleaning tool 34 by the primary amplitude increasing connecting body 82, is effected by making the mass and average cross-section al area of the input section 34 of the tool 34 of greater mass and greater average cross-sectional area than its output section 34", as is evident by referring to PEG- URES 1, 2 and 3. The principles of amplitude magnification of metal bodies is explained in greater detail in applicants US. Patent 2,792,674, now Reissue Patent Re. 25,0 33.

The cleaning tool or shoe may be composed of a substantially solid block of metal, such as an aluminum alloy, having high vibration transmitting capabilities and high tensile strength. As shown in FIGURES 2 and 3, the cleaning tool 34 may be made substantially rectangular in cross-section, and has substantially thesame. transverse thickness and thus presents substantially parallel side faces throughout its length. t will be further noted by referring to FIGURES 1 and 2 that the vibration input section 34' of the tool has a width as defined between its end face Sta-64a as shown in FIGURE 3, and measured in the plane of the grinding wheel to which it will be applied, which is substantially greater than the corresponding width of its output section 34". Thus, by making the output section 3 4" of lesser width than the input section 34 of the tool, the mean cross-sectional area and mass of the output section 34-" is substantially less than the mean cross-sectional area and mass of its vibration input sect-ion 34. As a result, substantial secondary amplitude magnification of the longitudinal vibrations injected into its vibration input end by the primary amplitude magnifying connecting body 82, is delivered to its cleaning face 1%. Since the cleaning shoes or tools 34 as illustrated in FIGURE 3 and FIGURES 4A to 5B inclusive and FIG- URE 6, are shown substantially full size in dimension, it will be noted that the actual arcuate length of the cleaning face 1%, as measured in the plane of the grinding Wheel to which it is applied, is in the order of approximately one-half inch in FIGURE .3, approximately five-eighths of an inch in FIGURES 4B and 5B, and approximately one and one-half inches in FIGURE 6. It has been found that a cleaning face 1% whose arcuate length, as measured in the plane of the grinding wheel, is in the order of approximately one-half to one and one-half inches, provides a sufficient shoe cleaning face area to insure eflective cavitation of the cleaning fluid in the spacing gap defined between the cleaning face lititl and peripheral grinding surface of the rotating wheel, irrespective of the thickness of the grinding wheel and the width of the cleaning face 1% applied thereto; provided a sufficient quantity of cleaning fluid is supplied to the spacing gap through the aperture port or ports in the cleaning face Mitt to insure a full layer of cleaning fluid in the spacing gap.

As explained above, the cleaning action produced by the apparatus of the present invention depends for its efliciency on the cavitation effect produced in the spacing gap provided between the cleaning face 1% of the cleaning tool and the grinding surface to be cleaned. To support cavitation therebetween, the fluid, preferably having a low surface tension and therefore high wetting ability, is continuously supplied by the coolant pump system into the spacing gap between the cleaning face of the tool and the Wheel surface. This fluid, when subjected to the high frequency vibration of the cleaning face 1% of the tool 34, engenders disruptive forces of great power at the surface of the wheel. These forces are effective to dis lodge particles and fragments embedded in the working surface of the grinding wheel and loosen them for easy removal. The cavitational fluid supplied to the surface of the wheel also provides an additional cooling effect which renders the grinding operation more efficient.

To ensure an adequate supply of cavitational fluid in the spacing gap between the cleaning face 101 of the cleaning shoe and the working surface of the rotating grinding wheel, a pair of side flanges 106 and a network of fluid discharge ports are provided in the cleaning face 1% of the tool, as illustrated in FIGURE 3 and FIGURES 4A to 5B inclusive and FIGURE 6. As shown in these figures, the inset cleaning face N of the tool is defined between the pair of side flanges 1% designed to snugly overlap the opposite sides of the grinding wheel with minimal rotational clearance therebetween. In practice, the inset cleaning face 160 may be formed by pushing the cleaning end of the tool intogrinding contact with the peripheral surface of the grinding wheel with which the tool is to be used, until the side flanges 1636 have been formed which snugly overlap the sides of the grinding wheel for approximately oneeighth of an inch. This procedure provides the desired minimal clearance between the side flanges 106 of the tool and the sides of the grinding wheel. It also provides the tool 34 with a substantially smooth cleaning face IMP which is in substantial arcuate conformity to the outer peripheral surface of the grinding wheel.

The tool 34 is then backed off from the peripheral surface of the grinding wheel by an amount suflicient to produce the desired depth of spacing gap for effective cavitational action during working rotation of the grinding wheel.

As shown most clearly in FIGURE 6, a blind end bore 102 is drilled into the shoe in the direction of the wheel rotation. The cavitational fluid is introduced into the open end of the bore 192 from the conduit 42 communicating therewith at the leading edge of the tool, or that edge where a point on the rotating grinding wheel will reach first. A plurality of fluid passages 104, radiating from the closed end bore 102, emerge at the cleaning face 100 in the form of small fluid discharge ports. As shown in the vertical section of FIG- URE 4A and the bottom view of the tool of FIGURE 4B, these passages 164 communicate with a plurality of fluid discharge ports which are distributed over the cleaning face 160 of the tool to provide a relatively uniformly distributed supply of fluid to the spacing gap. To permit proper cavitational action to occur, the apertures or ports in the face 160 of the tool should be relatively small with respect to the total area of the cleaning face 100. It has been found that small fluid discharge ports or holes of the character shown in FIGURES 4A and 4B and FIGURE 6, in the order of approximately onesixteenth to one-thirtysecond of an inch in diameter and arranged in the distribution pattern illustrated therein, provide adequate fluid supply to the cavitational gap between the cleaning face of the tool and the peripheral surface of the wheel to be cleaned. As the wheel rotates, the cavitational fluid runs down the wheel and into the work supporting tray 13, and is then filtered and recirculated. The cavitational fluid thereby provides an auxiliary cooling effect to enhance the overall efficiency of the grinding operation.

FIGURES A and 5B show an adaptation of the fluid supply arrangement shown in FIGURES 4A and 4B for a wheel of greater thickness. As is evident from FIGURES 5A and SB, this adaptation is substantially a duplication of the fluid supply arrangement shown in FIGURES 4A and 4B; namely, the inlet duct 42 is split into two branches 42a and 42b communicating with two parallel closed end bores 102a and 102b, respectively, within the working end of the cleaning tool. A suitable plurality of small passages 104 radiate from each of the closed end bores 102a and 102b, and terminate in individual fluid discharge ports uniformly distributed over the area of the cleaning face 106. It will be obvious that this multiplication of fluid feed bores, passages and discharge ports may be expanded to accommodate a wheel of any width.

In the rior art arrangements employing cavitational action to clean grinding wheel surfaces, it was thought that minimal clearance between the cleaning face of the shoe and the peripheral surface of the grinding wheel was necessary to promote eflicient cleaning action. For example, assuming that the full longitudinal stroking movement of the vibrating cleaning face of the tool was .001", the prior art suggests that the cleaning face of the tool should be placed approximately .001" to .002" from the peripheral working surface of the grinding wheel, when the cleaning face 1% of the tool is at rest or in mid-stroke position. The present inventors, however, have found that when such minimal depth spacing gap is used, relatively inefficient cleaning of the wheel results, and a substantial amount of deterioration of the cleaning face of the shoe occurs as a result of erosion and abrasion of the cleaning face 160 by dislodged particles. It was found that while such minimal spacing depth as suggested by the prior art, was suitable for cleaning the grinding surface of a relatively stationary or slowly rotating grinding Wheel, the tremendous centrifugal forces engendered by a grinding wheel rotating at operating speeds, made the prior art technique inapplicable to the cleaning problems presented by grinding wheels rotating at working speeds.

When a grinding wheel is rotating at production speeds, there exists at the periphery of the wheel, due to centrifugal effects, an equivalent gravitational force as observed by a particle on the peripheral surface of the rotating wheel of several thousand times the force of gravity. Obviously, the effect of this force is to throw off liquids that may be introduced on to the peripheral surface of the wheel as rapidly as they are applied thereto. In the present invention, the liquid is confined within the spacing gap between the cleaning face 100 of the shoe and the peripheral surface of the grinding wheel by the side flanges 106 of the tool, with the result that a full layer of cavitating fluid is built up and maintained in the spacing gap, notwithstanding the centrifugal forces engendered by wheel rotation. The present inventors have also found that by spacing the cleaning face 100 of the cleaning shoe at a distance from the grinding surface of the wheel substantially greater than that heretofore thought feasible, not only is improved cleaning action obtained, but the erosion to which the cleaning shoe is normally subjected when a minimum depth of spacing gap is used, is substantially completely avoided. Thus, applicants have found that by spacing the tool cleaning face to provide a spacing gap depth in the order of five-thousandths of an inch or more, substantially improved wheel cleaning results are achieved, and the life of the cleaning tool itself is extended indefinitely. Moreover, it has been found that this effect is achieved with spacing gap depths as high as .100". It has been found that with a spacing gap depth of approximately five-thousandths of an inch, for a 10" grinding wheel rotating at normal speed, effective cavitational action is produced at the grinding surface of the Wheel and at the same time no appreciable evidence of erosion occurs at the cleaning face 1% of the cleaning tool. The precise spacing gap depth to effect these desirable results, may of course vary with the diameter and speed of the wheel being used.

While the theory by which the present invention achieves its vastly superior results is not definitely known, a possible explanation is offered as follows. By virtue of the centrifugal eflect of the rapidly rotating grinding wheel, the cavitational liquid introduced into the spacing gap between the cleaning face of the tool and the wheel periphery is forced outward and up against the cleaning face of the tool to create a pressure thereat greater than that at the peripheral surface of the rotating wheel. In addition, the Bernoulli effect present at the peripheral surface of the rotating wheel due to its substantial velocity, decreases the pressure at the peripheral grinding surface. As is well known, the cavitational effect is enhanced in areas of reduced pressure and inhibited in areas of high pressure. In accordance with this suggested theory, therefore, the pressure differential created across the cavitational gap permits enhanced cavitation to occur at the peripheral surface of the rotating grinding wheel while substantially inhibiting erosion at the cleaning face of the tool. It will be understood, of course, that the above hypothesis is merely a suggested theory and the applicants do not wish to be limited thereby. Regardless of the applicable theory, however, there has been found to exist, when the depth of the spacing gap is substantially greater than heretofore thought feasible, a spacing gap depth at which cavitation is enhanced at the peripheral surface of the rotating grinding wheel, with substantially no evidence of erosion at the cleaning face of the tool.

In accordance with the present invention, the depth of the cavitational gap is increased beyond that contemplated by the prior art, but the clearance between the side flanges 1G6 and the sides of the grinding wheel are maintained minimal. This minimal clearance between the side flanges 106 of the tool and the sides of the grinding wheel increases the ability of the tool to trap a sufiicient supply of cavitational fluid in the spacing gap for effective cavitational action during working rotation of the grinding wheel. A secondary result of the increased depth of cavitational gap is to permit a somewhat longer vibration stroke to be used. It has been found that a longitudinal stroking movement of the cleaning face 10% (from peak to peak) of up to .002" may be employed in\the arrangement of the present invention with outstanding results. This longer stroke permits greater cavitational forces to be generated in the spacing gap with a consequently improved cleaning effect.

FIGURES 7 through 10 illustrate alternate methods of introducing fluid into the cavitational gap. Specifically, each of these figures illustrates a transverse slot 110 extending across the width of the cleaning face 100 of the tool and transversely between the side flanges 106 thereof, whereby fluid is introduced over the entire width of the cleaning face 100 at one time. In FIGURES 7 and 8, a slot 110 of substantially constant depth extends across the width of the cleaning face 104) of the tool adjacent the leading edge thereof. A closed end bore 192 is provided in the working end of the tool which communicates with the slot 110 by one or more fluid passages 111. The fluid supply conduit 42 is coupled to the open end of the closed end bore 162. As the wheel rotates, in the direction indicated by the arrow, the fluid supplied to the slot 110 is effectively withdrawn therefrom by the rotating movement of the wheel and an even layer of cavitational fluid fills the cavitational gap. One or more additional slots 110, supplied by one or more passages 111 radiating from the closed end bore 102, may be provided to increase the fluid supply.

In FIGURES 9 and 10, the depth of the slot 110, extending transversely across the width of the cleaning face 100 and between the side flanges 106 of the tool 34, is varied over its length to provide different rates of fluid to flow at different points across the width of the peripheral surface of the rotating grinding wheel. Such variable flow rates may be required by the particular type of work being ground or because of the characteristics of the wheel itself. In FIGURE 9, the slot 110 is shown having a deeper depth along its intermediate portion which tapers oif to relatively shallow depth portions adjacent the flanges 106. In this case, the greater fluid flow occurs near the center of the wheel periphery. In FIGURE 10, the depth 10 of the slot has a relatively shallow intermediate portion which gradually increases in depth towards the side flanges. In this case, greater flow occurs at the outer edges of the grinding wheel periphery.

It has sometimes been found in grinding ferrous metals that when a deep cut is taken by the grinding wheel, the debris created thereby, even though loosened by the cleaning tool 34, is not completely washed away by the cavitational fluid, but is carried along by the rotating grinding wheel into contact with the work surface being ground. This may result in a certain debris loading of the wheel and also prevents achieving a smoothly ground surface on the work. To remove these loosened debris particles before they can be carried back to the work surface by the rotating wheel, the apparatus illustrated in FIGURE 11 may be provided. As shown therein, the cleaning tool 34, such as shown in FIGURES 1 through 10, is mounted on the grinding machine in operating position with respect to the grinding wheel 12 as heretofore explained, and will operate in the manner discussed above. Mounted on the frame of the machine by any suitable journal bracket is a wheel 120, formed of a permanently magnetic material. The magnetic wheel has the same or greater thickness than the grinding wheel 12 and is arranged to barely contact the peripheral working surface thereof. The magnetic wheel 120 may be rotated by a belt drive driven by a small motor 122 also aflixed to the grinder frame in any convenient manner. It will be seen, that as the grinding wheel 12 rotates and the debris particles impacted on its peripheral surface are loosened by the tool .34, they are picked up by virtue of the magnetic attraction afforded by magnetic wheel 120 and removed from the surface of the grinding wheel. In order to remove these particles from the surface of the magnetic wheel 120, a chute 124 is provided having a forward edge in tangential contact with the magnetic wheel 120. As the surface of the magnetic wheel rotates past this edge, the magnetically attracted bits of metal debris are peeled off and projected up the chute 124 into a collection bin 132, which may be mounted on the frame of the grinder by support bracket 130. Thus, the particles of metal debris removed from the grinding wheel are disposed of before they have a chance to be drawn back into the work area and the grinder is thus able to take a deeper cut and still provide a smoothly ground Work surface with loading minimized.

To enable the operator to adjust and monitor the amplitude of vibration of the tool, a pickup device 33 (see FIG. 3) may be provided. The pickup device may be rigidly connected to the upper end of the tool 34, and opcrates to convert the vibratory motion of the tool 34 into electrical potentials which may be read on a meter. A suitable pick-up device for this purpose is disclosed in application Serial No. 855,932, filed November 27, 1959, for Ultrasonic Sensing Elements, assigned to the present assignee. In general, such a pick-up device comprises a pin of magnetostrictive material fastened to the upper end of the tool 34 and vibrates therewith. Arranged in operative relationship to the pin is a coil in which potentials proportional to the flux generated in the pin are induced. This flux is proportional to the amplitude of the vibration imparted to the pin by the tool 34. A meter is also provided which senses the potentials induced in the coil, and which may be calibrated to read amplitude of vibration. The operator merely adjusts the alternating current supplied to coil 85 until the meter, which may conveniently be mounted on the tool housing 70, indicates the desired amplitude. It will be realized of course, that other types of indicating means may be used to provide the desired amplitude indication.

It will be understood that the particular arrangements illustrated and described above are illustrative only and that various modifications and changes can be made therein without departing from the spirit and scope of the invention, as defined in the claims.

We claim: 7

1. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said Wheel is rotating at normal grinding speeds which includes, a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the Wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at frequencies in the high sonic and ultrasonic ranges, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of the wheel to which it is applied and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance sufiicient to induce cavitation at the peripheral grinding surface of such wheel and at the same time avoid any appreciable evidence of erosion of the cleaning face of the shoe when cavitational fluid is introduced therebetween, and means for introducing a cavitational fluid between said cleaning face and the peripheral grinding surface of such grinding wheel to which said shoe is applied, said cleaning shoe having a longitudinal length substantially corresponding to a half wavelength of sound or integral multiples thereof traveling longitudinally through the material of the shoe at the frequency of vibration, and which cleaning shoe further presents a vibration input section of substantially larger mass than the vibration output section thereof to thereby increase the amplitude of vibration of its cleaning face.

2. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes, a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at frequencies in the high sonic and ultrasonic ranges, a source of fluid capable of supporting cavitation, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of the wheel to which it is applied and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance sufficient to induce cavitation at the peripheral grinding surface of such wheel and at the same time avoid any appreciabie evidence of erosion of the cleaning face of the shoe when cavitational fluid is introduced therebetween, at least one aperture in the cleaning face of said shoe, and means for coupling said source of fluid through said shoe to said aperture and whereby the fluid is introduced between said cleaning face and the peripheral grinding surface of such grinding wheel to which the cleaning shoe is applied, said cleaning shoe having a longitudinal length substantially corresponding to a half wavelength of sound or integral multiples thereof traveling longitudinally through the material of the shoe at the frequency of vibration, and which cleaning shoe further presents a vibration input section of substantially larger mass than the vibration output section thereof to thereby increase the amplitude of vibration of its cleaning face.

3. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes, a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at frequencies in the high sonic and ultrasonic ranges, a source of fluid capable of supporting cavi- 12 tation, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of such wheel and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the pe ripheral grinding surface of such wheel a distance not substantially less than five-thousandths of an inch, at least one aperture in the cleaning face of said shoe, and means for coupling said source of fluid through said shoe to said aperture, and whereby said fluid is introduced between said cleaning face and the peripheral grinding surface of such grinding wheel to which said cleaning shoe is applied, said cleaning shoe having a longitudinal length substantially corresponding to a half wavelength of sound or integral multiples thereof traveling longitudinally through the material of the shoe at the frequency of vibration, and which cleaning shoe further presents a vibration input section of substantially larger mass than the vibration output section thereof to thereby increase the amplitude of vibration of its cleaning face.

4. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integral member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, said member having a longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into one end thereof, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, at least one fluid discharge aperture in said'cleaning face, a fluid entry opening in an exterior surface of said member located between the sides of said member, and a fluid passage in said member communicating with said aperture and said fluid entry opening whereby cavitational fluid introduced into said fluid passage will discharge through the aperture in said cleaning face, said member further having a vibration input section of larger mass than its vibration output section to thereby increase the amplitude of vibration of its cleaning face.

5. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding Wheel during normal grinding use thereof by means of a cavitational action induced at the peripheral grinding surface, a cleaning tool including an integral member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, said member having a longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into one end thereof, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, a plurality of spaced fluid discharge ports in said cleaning face, a closed end fluid entry bore in said member having a fluid entry opening in an exterior surface of said member which is located between the sides of said member, and a separate fluid passage in said member communicating with each of said ports and said fluid entry bore and whereby cavitational fluid introduced into said fluid passages will discharge through the ports in said cleaning face, said member further having a vibration input section of larger mass than 13 v its vibration output section to thereby increase the amplitude of vibration of its cleaning face.

6. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integral member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, said member having a longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into one end thereof, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, a fluid discharge slot extending transversely across said cleaning face and between the side flanges of said member, a fluid entry opening in an exterior end wall surface of said member which is located between the sides of said member, and a fluid passage in said member communicating with said fluid entry opening and said fluid discharge slot whereby cavitational fluid introduced into said fluid passage will discharge through the transverse slot in said cleaning face, said member further having a vibration input section of larger mass than its vibration output section to thereby increase the amplitude of vibration of its cleaning face.

7. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integral member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, said member having a longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into one end thereof, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, a relatively shallow fluid discharge slot extending transversely across said cleaning face between the side flanges of said member and which varies in depth along its length, a fluid entry opening in an exterior surface of said member and located between the sides of said member, and a fluid passage communicating with said slot and said fluid entry opening whereby cavitational fluid introduced into said fluid passage will discharge through the transverse slot in said cleaning face, said member further having a vibration input section of larger mass than its vibration output section to thereby increase the amplitude of vibration of its cleaning face.

8. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integral member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, said member having a longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths wheel to which it is to be applied with minimal clearance therebetween, a plurality of spaced fluid discharge slots extending transversely across said cleaning face and between the side flanges of said member, a closed end fluid entry bore in said member having a fluid entry opening in an exterior surface of said member which is located between the sides of said member, and a separate fluid,

passage in said member communicating with each of said slots and said fluid entry bore and whereby cavitational fluid introduced into said fluid passages will discharge through the transverse slots in said cleaning face, said member further having a vibration input section of larger mass than its vibration output section to thereby increase the amplitude of vibration of its cleaning face.

9. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool which includes an integral member designed to be longitudinally vibrated when the vibration input end thereof is connected to a source of high frequency vibrations, the vibration output end of said member presenting a cleaning face substantially in shape conformity with the grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, said member having a longitudinal length substantially corresponding to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into the vibration input end thereof, said member also having its vibration input end of greater cross-sectional area than its vibration output end so that said member operates as an acoustical impedance transformer which magnifies the amplitude of longitudinal vibrations applied to its input end and delivered to said cleaning face, at least one aperture in said cleaning face, a fluid entry opening in an exterior surface of said member and located between the sides of said member, and a fluid passage in said member communicating with said aperture and said fluid entry opening whereby cavi-' tational fluid introduced into said fluid passage will discharge through the aperture in said cleaning face.

10. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a clean ing tool including an integral member designed to be longitudinally vibrated when the vibration input end thereof is connected to a source of high frequency vibrations, said member presenting a vibration input section and a vibration output section having a combined longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrationsinjected into the vibration input end thereof, said vibration output section being substantially rectangular in cross-section and presenting a vibration output end which is of lesser cross-sectional area than the mean cross-sectional area of said input section so that said member operates as an acoustical impedance transformer which magnifies the amplitude of longitudinal vibrations applied to its input end and delivered to the output end thereof, the output end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced'to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, at least one aperture in said cleaning face, a fluid entry opening in an exterior surface of the vibration output section of said member, and a fluid passage in said member communicating with said aperture and said fluid entry opening whereby cavitational fluid introduced into said fluid passage will discharge through the aperture in said cleaning face.

11. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said Wheel is rotating at normal grinding speeds which includes; a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at frequencies in the high sonic and ultrasonic ranges, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of the wheel to which it is applied and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance suflicient to induce cavitation at the peripheral grinding surface of such wheel and at the same time avoid any appreciable evidence of erosion of the cleaning face of the shoe when cavitational fluid is introduced therebetwcen, means for introducing fluid between said cleaning face and the peripheral grinding surface of such grinding wheel, a device for picking up magnetic debris particles loosened from the grinding surface, and means for mounting said device behind said shoe and closely adjacent the peripheral grinding surface of such grinding wheel to which it is applied.

12. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes; a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at frequencies in the sonic and ultrasonic ranges, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of such wheel and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance sufficient to induce cavitation at the peripheral grinding surface of such wheel and at the same time avoid any appreciable evidence of erosion of the cleaning face of the shoe when cavitational fluid is introduced therebetween; means for introducing fluid between said cleaning face and the peripheral grinding surface of such grinding wheel; a magnetic wheel for picking up loosened magnetic particles from the grinding surface of such grinding wheel, means for stripping magnetic particles accumulating on the magnetic Wheel, and means for mounting said magnetic wheel behind said shoe and closely adjacent the peripheral grinding surface of such grinding wheel to which it is applied.

13. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said Wheel is rotating at normal grinding speeds which includes; a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at high frequencies, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of such wheel and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance suflicient to induce cavitation at the peripheral grinding surface of such wheel, at least one fluid discharge aperture in the cleaning face of said shoe, a fluid passage in said shoe communicating with .said fluid discharge aperture and an opening in the lead surface of said shoe which is positioned between the sides thereof, a fluid supply conduit communicating with said opening and a fluid source, and an adjustable valve in said fluid supply conduit operative to regulate the fluid volume discharged from said aperture and whereby a fluid layer capable of effective cavitation may be injected into the spacing gap defined between the cleaning face of the shoe and the grinding periphery of such grinding wheel to which the shoe is applied, during working rotation of such grinding wheel.

14. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes; a cleaning shoe having a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, means to vibrate said cleaning shoe at high frequencies, means for mounting said cleaning shoe so that its longitudinal axis extends substantially radially of such wheel and with its flanges overlapping the sides of such wheel and with said cleaning face spaced from the peripheral grinding surface of such wheel a distance suflicient to induce cavitation at the peripheral grinding surface of such wheel, a plurality of spaced fluid discharge ports in said cleaning face, a closed end fluid entry bore in said member having a fluid entry opening in an exterior surface of said member which is located between the sides of said member, a separate fluid passage in said member communieating with each of said ports and said fluid entry bore, a fluid suppply conduit communicating with said fluid entry opening and a fluid source, and an adjustable valve in said fluid supply conduit operative to regulate the fluid volume discharge from said apertures and whereby a fluid layer capable of effective cavitation may be injected into the spacing gap defined between the cleaning face of the shoe and the grinding periphery of such grinding wheel to which the shoe is applied, during working rotating of such grinding wheel.

15. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integal member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, a plurality of spaced fluid discharge ports in said cleaning face, a closed end fluid entry bore in said member whose longitudinal axis is substantially parallel to said flanges and whose open fluid entry end intersects a wall surface of said member which is substantially perpendicular to said flanges, and a plurality of fluid passages radiating from said fluid entry bore and individually communicating with each of the respective fluid discharge ports in said cleaning face, said member having a longitudinal length substantially corresponding to a half wavelength of sound or integral multiples thereof traveling longitudinally through the material of said member at the frequency of vibration, and which member further presents a vibration input section of substantially larger mass than the vibration output section thereof to thereby increase the amplitude of vibration of its cleaning face.

16. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integal member designed to be longitudinally vibrated when one end thereof is connected to a source of high frequency vibrations, the other end of said member presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, a plurality of spaced fluid discharge ports in said cleaning face which present at least two groups of discharge ports, a closed end fluid entry bore for each group of discharge ports, each of said fluid entry bores extending into said member in the direction substantially parallel to said side flanges and whose fluid entry end intersects a wall surface of said member which is substantially perpendicular to said side flanges, and a plurality of fluid passages radiating from each of said fluid entry bores and individually communicating with the respective fluid discharge ports of one port group, and whereby cavitational fluid introduced into each of said fluid entry bores will discharge through the respective ports of each port group in said cleaning face, said member having a longitudinal length substantially corresponding to a half wavelength of sound or integral multiples thereof traveling longitudinally through the material of said member at the frequency of vibration, and which member further presents a vibration input section of substantially larger mass than the vibration output section thereof to thereby increase the amplitude of vibration of its cleaning face.

17. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool including an integal member designed to be longitudinally vibrated when the vibrating input end thereof is connected to a source of high frequency vibrations, said member presenting a substantially rectangular vibration input section and a substantially rectangular vibration output section, the output end of said vibration output section presenting a cleaning face substantially in shape conformity with the peripheral grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, at least one fluid discharge aperture in said cleaning face, a fluid entry opening in an exterior surface of the vibration output section of said member, and a fluid passage in said member communicating with said aperture and said fluid entry opening whereby cavitational fluid introduced into said fluid passage will discharge through the aperture in said cleaning face, the output section and input section of said member having a combined longitudinal length substantially equal to a half wavelength or an integral number of half wavelengths of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into the vibration input end thereof, the mean dimension of said output section measured in a direction parallel to said side flanges being less than the corresponding mean dimension of said input section which thereby reduces the mean cross-sectional area of said output section to less than the mean cross-sectional area of said input section so that said member operates as an acoustical impedance transformer which magnifies the amplitude of longitudinal vibrations applied to its input end and delivered to the cleaning face thereof.

18. In apparatus for removing debris from the peripheral grinding surface of a rotating grinding wheel during normal grinding use thereof by means of cavitational action induced at the peripheral grinding surface, a cleaning tool which includes an integral member designed to be longitudinally vibrated when the vibration input end thereof is connected to a source of high frequency vibrations, the vibration output end of said member presenting a cleaning face substantially in shape conformity with the grinding surface to which it is to be applied, said cleaning face being defined between side flanges spaced to telescope over the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, said member presenting a vibration input section and a vibration output section having a combined longitudinal length substantially corresponding to a half wavelength of sound traveling longitudinally through the material of said member at the frequency of the vibrations injected into the vibration input end thereof, said output section having a mean dimension measured in a direction parallel to said side flanges which is less than the corresponding mean dimension of said input section which thereby reduces the mean cross-sectional area of said output section so that said member operates as an acoustical impedance transformer which magnifies the amplitude of longitudinal vibrations applied to its input end and delivered to said cleaning face, a plurality of spaced fluid discharge ports in said cleaning face, a closed end fluid entry bore extending into said vibration output section in a direction substantially parallel to said side flanges and having its entry end opening at a wall surface of said output section which is substantially perpendicular to said side flanges, and a plurality of fluid passages radiating from said fluid entry bore and individually communicating with the respective fluid discharge ports and whereby cavitational fluid introduced into said fluid entry bores will discharge through the respective ports in said cleaning face.

19. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes, a magnetostrictive transducer, means for energizing said transducer to cause the same to longitudinally vibrate at high frequency, a connecting body rigidly fixed to one end of said transducer, said connecting body having a longitudinal length substantially corresponding to a half wavelength of sound traveling longitudinally through said body at the frequency of the vibrations injected into the transducer attached end thereof when said transducer is enerized, said connecting body being further shaped and formed to operate as an acoustical impedance transformer which provides a primary magnification of the amplitude of longitudinal vibrations applied to its input end and delivered to its output end, a cleaning tool presenting a vibration input section fixedly secured to the output en of said connecting body and a vibration output section which presents a cieaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, the vibration input and output sections of sai tool having a combined longitudinal length which substantially corresponds to a half wave length of sound traveling longitudinally through said tool at the frequency of vibrations injected into its input section by said connecting body, said vibration output section having a mean cross-sectional area which is less than the mean cross-sectional area of said input section whereby said tool operates as an acoustical impedance transformer which provides a secondary amplification of the longitudinal vibrations delivered to the cleaning face thereof, and means for introducing a caviational fluid to the cleaning face of said tool.

20. Apparatus for removing debris from the peripheral grinding surface of a grinding wheel while said wheel is rotating at normal grinding speeds which includes; a vibrator unit comprising a magnetostrictive transducer, means for energizing said transducer to cause the same to longitudinally vibrate at high frequency, a connecting body rigidly fixed to one end of said transducer, and a cleaning tool rigidly secured to the vibration output end of said connecting body, said connecting body having a longitudinal length substantially corresponding to a half Wave length of sound traveling longitudinally through said body at the frequency of the vibrations injected into the transducer attached end thereof when said transducer is energized, said connecting body also having a laterally extending flange at approximately the node of longitudinal vibration which defines a vibration input section on one side of said nodal flange and an output section on the other side of said nodal flange, said vibration input section being of greater mass than said output section so that said connecting body operates as an acoustical impedance transformer which provides a primary magnification of the amplitude of longitudinal vibrations applied to its input end and delivered to its output end, a resilient ring embracing said nodal flange, means for supporting said resilient ring and vibrator unit, said cleaning tool presenting a vibration input section fixedly secured to the output end of said connecting body and a vibration output section which presents a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, a pair of flanges on opposite sides of said cleaning face spaced to closely overlap the sides of the grinding wheel to which it is to be applied with minimal clearance therebetween, the vibration input and output sections of said tool having a combined longitudinal length which substantially corresponds to a half wavelength of sound travelinglongitudinally through said tool at the frequency of vibrations injected into its input section by said connecting body, said vibration output section having a mean cross-sectional area which is less than the mean cross-sectional area of said input section whereby said tool operates as an acoustical impedance transformer which provides a secondary amplification of the longitudinal vibrations delivered to the cleaning face thereof, and means for introducing a cavitational fluid to the cleaning face of said tool.

21. Apparatus for removing debris from the peripheral grinding surface of a grinding Wheel while said wheel is rotating at normal grinding speds which includes; a vibrator unit comprising a magnetostrictive transducer, means for energizing said transducer to cause the same to longitudinally vibrate at high frequency, a connecting body rigidly fixed to one end of said transducer, and a cleaning tool rigidly secured to the vibration output end of said connecting body which presents a cleaning face substantially conforming to the peripheral grinding surface of the wheel to which it is to be applied, said connecting body having a longitudinal length substantially corresponding to a half wavelength of sound traveling longitudinaliy through said body at the frequency of the vibrations injected into the transducer attached end thereof when said transducer is energized, said connecting body also having a laterally extending flange at approximately the node of longitudinal Vibration which defines a vibration input section on one side of said nodal flange and an output section on the other side of said nodal flange, said vibration input section being of greater mass than said output section so that said connecting body operates as an acoustical impedance transformer which magnifies the amplitude of longitudinal vibrations applied to its input end and delivered to its output end, a mounting member in surrounding relation to said connecting body, a resilient sealing ring compactly positioned between the nodal flange of said connecting body and said mounting member, a retainer ring detachably connected to said mounting member which supports said sealing ring and vibrator unit, a housing supported by said mounting member and enclosing said transducer and a part of said connecting body, means for introducing a transducer coolant to said housing and withdrawing warmed coolant therefrom, and means for introducing a cavitational fluid to the cleaning face of said tool.

References Cited in the file of this patent UNITED STATES PATENTS 2,813,377 Duran Nov. 19, 1957 2,858,652 Luthman et al. Nov. 4, 1958 2,949,707 Staelin Aug. 23, 1960 

1. APPARATUS FOR REMOVING DEBRIS FROM THE PERIPHERAL GRINDING SURFACE OF A GRINDING WHEEL WHILE SAID WHEEL IS ROTATING AT NORMAL GRINDING SPEEDS WHICH INCLUDES, A CLEANING SHOE HAVING A CLEANING FACE SUBSTANTIALLY CONFORMING TO THE PERIPHERAL GRINDING SURFACE OF THE WHEEL TO WHICH IT IS TO BE APPLIED, A PAIR OF FLANGES ON OPPOSITE SIDES OF SAID CLEANING FACE SPACED TO CLOSELY OVERLAP THE SIDES OF THE GRINDING WHEEL TO WHICH IT IS TO BE APPLIED WITH MINIMAL CLEARANCE THEREBETWEEN, MEANS TO VIBRATE SAID CLEANING SHOE AT FREQUENCIES IN THE HIGH SONIC AND ULTRASONIC RANGES, MEANS FOR MOUNTING SAID CLEANING SHOE SO THAT ITS LONGITUDINAL AXIS EXTENDS SUBSTANTIALLY RADIALLY OF THE WHEEL TO WHICH IT IS APPLIED AND WITH ITS FLANGES OVERLAPPING THE SIDES OF SUCH WHEEL AND WITH SAID CLEANING FACE SPACED FROM THE PERIPHERAL GRINDING SURFACE OF SUCH WHEEL A DISTANCE SUFFICIENT TO INDUCE CAVITATION AT THE PERIPHERAL GRINDING SURFACE OF SUCH WHEEL AND AT THE SAME TIME AVOID ANY APPRECIABLE EVIDENCE OF EROSION OF THE CLEANING FACE OF THE SHOE WHEN CAVITATIONAL FLUID IS INTRODUCED THEREBETWEEN, AND MEANS FOR INTRODUCING A CAVITATIONAL FLUID BETWEEN SAID CLEANING FACE AND THE PERIPHERAL GRINDING SURFACE OF SUCH GRINDING WHEEL TO WHICH SAID SHOE IS APPLIED, SAID CLEANING SHOE HAVING A LONGITUDINAL LENGHT SUBSTANTIALLY CORRESPONDING TO A HALF WAVELENGTH OF SOUND OR INTEGRAL MULTIPLES THEREOF TRAVELING LONGITUDINALLY THROUGH THE MATERIAL OF THE SHOE AT THE FREQUENCY OF VIBRATION, AND WHICH CLEANING SHOE FURTHER PRESENTS A VIBRATION INPUT SECTION OF SUBSTANTIALLY LARGER MASS THAN THE VIBRATION OUTPUT SECTION THEREOF TO THEREBY INCREASE THE AMPLITUDE OF VIBRATION OF ITS CLEANING FACE. 